Part one draws a lot of biblical parallels. In addition to O the Scientist being God, Ahrima can be seen as a Composite Character between Lucifer (whose name means "light bringer" and who also became a Fallen Angel due to excess of pride) and Eve (who is tempted by a talking animal into committing the world's first sin).
In one stage version, Pallis stabs the Doctor shortly after he enters. You can see it here.
Also, while a century is indeed a long passage of time, it is treated as multiple generations, given that Adakias’ surprise that Ahrima is his ancestor. A century isn’t all THAT long, it would have made more sense if it was maybe a couple of centuries.